github.com/gofiber/fiber/v3 cache middleware can mix responses across query parameters

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Fiber is a web framework for Go. In github.com/gofiber/fiber/v3 versions through 3.1.0, the default key generator in the cache middleware uses only the request path and does not include the query string. As a result, requests for the same path with different query parameters can share a cache key and receive the wrong cached response. This can cause response mix-up for query-dependent endpoints and may expose data intended for a different request. This issue is fixed after version 3.1.0.

Source published

5 May 2026 12:40:19 UTC

Source modified

5 May 2026 15:04:02 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Fiber is a web framework for Go. In github.com/gofiber/fiber/v3 versions through 3.1.0, the default key generator in the cache middleware uses only the request path and does not include the query string. As a result, requests for the same path with different query parameters can share a cache key and receive the wrong cached response. This can cause response mix-up for query-dependent endpoints and may expose data intended for a different request. This issue is fixed after version 3.1.0.

Source published

May 5, 2026, 12:40:19 PM (timezone not stated)

Source modified

May 5, 2026, 3:04:02 PM (timezone not stated)

Observed here

7 Nov 2026 06:36:32 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 3.1 · 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Fiber is a web framework for Go. In github.com/gofiber/fiber/v3 versions through 3.1.0, the default key generator in the cache middleware uses only the request path and does not include the query string. As a result, requests for the same path with different query parameters can share a cache key and receive the wrong cached response. This can cause response mix-up for query-dependent endpoints and may expose data intended for a different request. This issue is fixed after version 3.1.0.

Source published

5 May 2026 13:16:28 UTC

Source modified

26 Oct 2026 19:10:00 UTC

Observed here

27 Oct 2026 08:06:30 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

### Summary Fiber cache middleware's default key generator uses only `c.Path()` and does not include the query string. As a result, requests like `/?id=1` and `/?id=2` can map to the same cache key and share the same cached response. This can cause response mix-up (cache poisoning-like behavior) for endpoints where response content depends on query parameters. ### Details Default configuration in cache middleware: - `KeyGenerator: func(c fiber.Ctx) string { return utils.CopyString(c.Path()) }` References: - https://github.com/gofiber/fiber/blob/main/middleware/cache/config.go#L90-L92 - https://github.com/gofiber/fiber/blob/main/middleware/cache/cache_test.go#L599-L621 The existing test demonstrates that when handler output depends on query parameter `id`, a second request with a different query still returns the first cached response (cache hit), confirming query is not part of the default cache key. ### PoC Minimal PoC: ```go package main import ( "log" "github.com/gofiber/fiber/v3" "github.com/gofiber/fiber/v3/middleware/cache" ) func main() { app := fiber.New() app.Use(cache.New()) // default config app.Get("/", func(c fiber.Ctx) error { return c.SendString(c.Query("id", "1")) }) log.Fatal(app.Listen(":3000")) } ``` Reproduction: 1. `GET /?id=1` - Cache miss - Response body: `1` 2. `GET /?id=2` - Cache hit - Response body: `1` (expected `2`) Local verification command used: ```bash go test ./middleware/cache -run Test_Cache_WithNoCacheRequestDirective -count=1 ``` Observed result: test passes, confirming this is current behavior. ### Impact - Responses that should vary by query parameters can be mixed between requests. - In real deployments, this may leak or corrupt user/tenant-specific content if query parameters influence context or data selection. - This is deployment-dependent but security-relevant, and not safe-by-default for query-variant responses. ### Suggested remediation - Change default cache key generation to include path + normalized query string (or canonicalized original URL). - Keep ability for custom key generators. - Add explicit documentation warning that path-only keying is unsafe for query-dependent responses.

Source published

28 Apr 2026 22:28:14 UTC

Source modified

24 Jul 2026 19:11:27 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Publisher rating · MODERATE

Fiber: Cache middleware key generator ignores query string in github.com/gofiber/fiber

Source published

24 Jul 2026 18:35:55 UTC

Source modified

24 Jul 2026 19:00:21 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.